<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>修改页面内容</title>
</head>
<body>
    <input type="button" value="播放">
    <script>
        let btn=document.querySelector('input');
        btn.onclick=function(){
            if(btn.value=='播放'){
                btn.value='暂停';
            }else{
                btn.value='播放';
            }
        }
    </script>
</body>
</html>